Along with development of a UMTS (Universal Mobile Telecommunications System), the number of supported frequency bands has been increasing. Conventionally, in order for the UMTS to support a plurality of frequency bands, it is necessary to provide a plurality of power amplifiers (PA) and a plurality of duplexers (Dup) in accordance with the number of the plurality of frequency bands. It is noted that the UMTS includes a W-CDMA, a TD-CDMA, and the like. FIG. 6 is a block diagram showing the configuration of a conventional multiband wireless apparatus 50 as described above. As shown in FIG. 6, the conventional multiband wireless apparatus 50 includes: an RFIC 51; an amplifying circuit 52 including a plurality of power amplifiers (PA) connected in parallel; a plurality of duplexers (Dup) corresponding to the respective power amplifiers; and an antenna switch (ANT-SW) 54. Here, for the purpose of simplifying the description, FIG. 7 shows a simplified configuration of the multiband wireless apparatus 50, which is obtained by, in FIG. 6, decreasing each of the number of the power amplifiers and the number of the duplexers to two.
FIG. 7 is a simplified diagram showing a part of the configuration of the conventional multiband wireless apparatus 50 shown in FIG. 6. As shown in FIG. 7, the multiband wireless apparatus 50 includes: the RFIC 51; two power amplifiers 521 and 522 connected in parallel; two duplexers 531 and 532 corresponding to the respective power amplifiers 521 and 522; and the antenna switch 54. A control section (not shown) switches the connection of the antenna switch 54 between the duplexer 531 and the duplexer 532 in accordance with a frequency band to be supported, thereby switching a power amplifier and a duplexer to be used, between the power amplifiers 521 and 522 and between the duplexers 531 and 532. However, in the conventional multiband wireless apparatus 50, there is a problem that along with increase in the number of supported frequency bands, the number of components such as power amplifiers and duplexers increases, and thereby the circuit scale increases.
Then, in response to the increase in the UMTS bands, there has been taken an approach of using a wideband PA and a tunable duplexer capable of switching its band to a desired frequency, to reduce the number of parallel transmission circuits, thereby suppressing the increase in the number of components (see, for example, Non-Patent Literature 1). FIG. 8 is a block diagram showing the configuration of a conventional multiband wireless apparatus 60 disclosed in Non-Patent Literature 1. As shown in FIG. 8, the conventional multiband wireless apparatus 60 includes: an RFIC 61; an amplifying circuit 62 including a wideband PA 621; and a tunable duplexer 63. Thus, the conventional multiband wireless apparatus 60 uses the wideband PA 621 and the tunable duplexer 63 in response to the increase in the UMTS bands, thereby suppressing the increase in the number of components.